DEER FACTS AND DEER FENCES
March 23, 2022
The deer facts covered here don’t deal with general deer behavior but rather with those kinds of deer behavior that tell us whether, how, and where to build deer fences.
How High Will Deer Jump?
Back in the “old days” before 2000, people used to think that white-tailed deer could jump 10 or even 12 feet high. It turns out they either won’t or can’t. In fact, hardly any will jump a 7-foot fence even in a panic, and virtually none will jump a 7-footer just to get a meal. Therefore, 8-foot fences aren’t needed for exclusion purposes, and economical 7-footers (we sell mostly 7-foot fences) do a fine job protecting estates, yards, and gardens against deer. For more on this see our article on Deer Fence Height.
Deer vision may relate to this. Deer have acute senses of smell and hearing and reasonable nighttime vision, but their daytime vision is poor. Also, because their eyes are on the sides of their heads (to better spot predators), they cannot triangulate; hence their depth perception is deficient. All this means they have trouble seeing the top of a deer fence, a difficulty that deer fence designers enhance by not placing boards or pipes along the top and instead leaving the top of the fence bare.
Finally, deer don’t like jumping into narrow spaces. So if 7-foot fences are barred by homeowner associations or local ordinances, two four-foot fences separated by three feet or so provide an expensive but effective option. Another alternative here is a 6-foot fence, which is not fully reliable but which keeps out deer most of the time. This 6-foot fence can be made fully reliable if it is angled outward at 45 degrees; but such a fence is unwieldy, costly, hard to install, and vulnerable to snow and falling branches.
Deer Facts: Food Choice
Deer relish certain plants like hostas and tend to spurn others. However, this tends to be a relative matter that depends upon how hungry they are – as demonstrated by their willingness to devour the dormant buds of trees in winter when food is scarce. That means if one relies on deer-resistant plants to save one’s garden, this will only work until the local deer get hungry enough to change their dining rules and devour the “resistant” plants.
Besides eating tree buds (a major problem for dwarf or young trees in orchards), male deer commonly damage trees by rubbing against them with their antlers. The old antlers fall off in winter, and new ones grow in spring. While growing, the new antlers are covered with a tissue known as “velvet” which provides them with a blood supply. When the velvet’s job is done, typically in late summer or early fall, the deer remove it by rubbing their antlers against tree trunks, commonly removing a good deal of tree bark in the process. This can and does kill or seriously damage trees, especially young trees, in orchards, landscape plantings, arboretums, and other places frequented by the deer.
Deer Facts on Fence Penetration
Deer don’t want to go over fences 7 feet tall or higher, but they can penetrate them other ways. For instance, adult white tails can run up to 40 miles an hour. So, if they slam into a barrier deer fence (especially a plastic fence) full tilt they will probably break through. However, they won’t do this on purpose (would you?). That’s why it’s a good idea to put little white warning flags on a low-visibility deer fence when it first goes up, so that the deer (with their visual limitations) will see the flags and realize something’s there.
Also, because deer are very much creatures of habit, a doe following her accustomed path will commonly try to remove or break through anything that blocks it. For this reason, a doe encountering a deer fence for the first time may turn her nose into a sort of fist and pound away at the fence for hours until (if it’s a plastic fence) the fence breaks. This doesn’t happen with great frequency, but it happens.
More often (this is a really common problem) rabbits or woodchucks seeking passage through a plastic deer fence will gnaw small holes near the bottom. As noted, the deer don’t want to go over the fence, so they look for ways under it. When they find one of these small holes they will often jam their heads in, break a few corner bonds (the fencing is very strong but so are the deer), enlarge the hole and penetrate the fence. For this reason, informed gardeners and others commonly install a vertical strip of metal fencing (pvc-coated metal hexagrid, welded wire, or small-mesh chicken wire) some 2 feet tall along the bottom of a plastic deer fence to prevent rabbits and woodchucks from making holes.
Deer and Repellents
Deer get used to repellents. That is, even if the repellents don’t get washed away by rain, in time the deer may become accustomed to them – plenty accustomed to eat protected plants. The same applies to motion-activated water sprayers, noisemakers, and ultrasound generators. These clever gadgets work for a while; but because the deer tend to get used to them, their long-term results are often disappointing.
Jonathan Leonard, Manager
McGregor Fence Company LLC
Ideaman, Inc. Whitetail Deer Facts and Trivia, Information and Photos. American Expedition, 2015.
Vercauteren KC, Vandeelen T, Lavelle MJ, and Hall W. Assessment of Abilities of White-tailed Deer to Jump Fences. Journal of Wildlife Management 74(5): 1378-1381, 2010.
Woodstream Corporation. Deer Facts. Havahart.com, 2022.